Epson 4490 Noise

[cool breeze]

Hi,
I just bought an Epson 4490 from Craigslist to scan my 35mm and 120 film negatives. I noticed when previewing, before scanning (also occurs when scanning, but at a much slower pace), the scanner starts making a loud banging noise half-way through. Does anybody have any idea what this is and/or how to fix it?

Thanks